Impulse repeater



P 5 1943- K. w. PFLEGER 2,328,671

IMPULSE REPEATER Filed Nov. 13, 1941 FIG.

RIO

INPUT ourpur vRM TIME

INVENTOR i KWPFLEGER ATTORNEY Patented Sept. 7, 1943 Bell Telephone Laboratories, Incorporated, 5

p New York, N. Y a corporaticnoi New York 7 5 Application November 13, 1941; Serial'No.418,982 I 3 "SCIaimSQ itclieo-nv) W This inventionrelates to amplifying, repeating and reshaping instrumentalities for low frequency current impulsesiof thejtyp'eused in direct current telegraphy.

There have previously been proposed various arrangements of gas discharge tubes for repeating or amplifying low frequency impulses;

One of the objects of the present invention is .ede m me.- By virtue of min-aim which to improve the operation of such arrangements by providing modified and improved circuits therefor. A feature cf improvement consists in arrangements whereby the form of the output Wave may be improvedby'an "over-shooting effect which increases the 'amplitudeof the front end of the outgoing impulse. f

Another feature of improvement i with respect to wave shaping in generalnji Still another feature f consists in circuits "de- P signed to minimize or reduce so-called ft elegraph I phethump 'or receiving end thump]? nomenon results inthe use of electromagnetic relays and some other types of relays by the productionof an K induced vol a e which feeds back into the line which constitutes the input circuit. This is objectionable on telegraph systems composited with telephone systems.

-Other features and 'objectsof the'invention will appearirom the following description takenwith the accoinpanyingdrawing which: j'-

*Fig. 1 comprisesa generalized schematic ar rangement in accordance with the invention;

Fig. 2 discloses an arrangement which may be i I connected to each of the sets of terminals 1,, :2 of

the circuitof Fig.1 to supply a duenchingyoltage to each of the sets of terminals 3, 4 thereof; Figs. 3 and 4 illustrate modification .which may bfesubstitutedffor the arrangement'of Fig. 2; and' U Fig, 5:15 a diagram illustrating the typecf quenching vpltage supplied to the output circuit of each tube' when the arrangement Iof Fig. 2 is employed inFig. 1.

cireuitwhich supplies polar impulses, that is impulses a part of'which are in one direction and apart ofwhichare in another directio'nhto be amplified. [Currents incident to theseimpulses now through resistances RI and B2. thereby'ap takes place in the tubeithe grid very largely loses control over the tube'i'in the discharging condition and the; discharge jjcontinues toflow independently' jof all potentials of the grid within the normal working range so long as a suitablepotential is applied between the anode and theicathodebc Ihe anode circuit of tube H passes from positive battery through theresistances RTand, R5.

The anode circuit of the ether tube passes from the same positive battery through the-resistances RA-and R6. The resistance R3 and R4 are included in an outgoing line oroutput path labeled ifo p t Rectangles-Ntand N 2 each include fourterminals designated L1 and 3, 4 toi which various kinds Offcircuits may be attached; f p

One such circuit is illustrated in Fig. 2 in which the network N! or N2 comprises an amplifying high vacuum cr other suitable, amplifying tube preferably'designed tohandle considerable power.

.The input circuit comprises atransformer primary '5; aresistance IR! and a capacity C2 and the secondary winding 6 of the transformer is connected directly to" the grid of the power tube P; {The output circuit may be connected to the terminals 3, 4 cfFig; 1. Thusfit is connected directly across resistanceRS or R6 as the case maybe.

"In considering the operationlet it be supposed,

for the purpose of establishing an initial condition; that neither tube ll nor I2 is discharging.

Then assume "an impulse arriving over the input circuit causes current to flow through the resistances BI and. R2 in such a direction as to make the grid of tube H positive. This causes thecurrent to flow in the anodecathode circuit In Fig. 1, the in ut circuit eeled inp'u 7? may 1 compriseterminals of a telegraph line or other .to said tube and, conseq e y. through the r sistance R3 which results in the impression of a voltage drop upon or the flow of 'a' corresponding current in the output circuit. Upontheinitial discharge of the tube ll thefcurre'nt rises suddenly and a large voltage is'applied across the terminals l, 2 which is amplifiedjby the power tube Pfandj applied in amplified form to terminals 3 4. The lower curve of Fig. 5 show the form of voltage impulse appliedto the grid of tube P plyingvoltag es to the input circuits of the tubes u and I2 which are of a well kncwn typeso designed that a certain magnitudeof positive or reduction of negative potential applied to the grid thereof causes a discharge between the anandQtheupper'curve shows/the form of current wave or impulse flowing through the resistance R6.- Inasmuch as we have assumed thattube' l2 was'not discharging, this currentimpulse will have no particular effect upon tube I Z. Now let us assume that the incomin impulse reverses sign in suchia manner as to make the grid of This. will cause the tube II to become extinguished; that is, the discharge therein will cease.

Because of the amplifying power of the tuhe P, the energy in the impulse illustrated in the upper part of Fig. 5 will be considerable, thereby 1 applying a large and consequently an effective quenching voltage to the tube. Moreover, since.

at this time the grid ofitube II has become negative and remains negative so'long asthe impulse which initiated the discharge tube;

l2 is continuing, there will be no further discharge in tube II.

positive and negative impulses, corresponding-to the incoming impulses. The amount of energy taken fromithe output circuits of either tube II I ortube IZto quench theother tube is relatively :sinallfi, r, Y I, I l H A significant feature of theinvention resides in'the fact that the impedance of resistances 3,

R LvRiand l'tfiis almost entirely dissipative 'and that the; quenching voltage, is not derivedufr'om alcond'ensrg This, results in much more rapid building up'of theinipulsesand a more fiect'ive extinguishment of thetubes than occurs in, the case wherefcondensers are utilized as the con pling impedance. It maybe shown that with' the arrangement disclosed the initial portion) of 1 an denserC3, and the secondary circuit mayyconsist of, the. secondary winding 6.;o-f a transformer 1 nglalarge number; of 'turnsinseries with a nserCi; and a resistance, R9. [If the. re:-

s'ista es Ril andRfifare properly proportioned, it

may; be 'possiblefto obtain suffici'ent energy-from the outputs of the transducers 'or networks NI andNZ to extinguish the gas tubes and atj the same time avoid prolonged transient impulses Eorexample, suppose tube I2, draws current and II I does not. Then a reversal of polarity of the input signal suddenly causes tube II. tov fire, ,Therefore,"the current in resistance B3 jumps to a higher value. T he transient currentLinRIS produces, aftransient Voltage across terminalsv I and 2 of Fig. 3fwhichis stepped up by the .tra s1- former; sothat thelvoltage which it transmits; to RBHis'suflicient to 11educe,the}plate potential of tube, 12 to .z r'o. or below, thusfeXtinguishiI-lg the latter; When the, transformer isfide'al the transienti isjnot. prolonged. In a practical trans fo rrner'havingleakage 'reactance, the series're sister's as, and RSQand the condensers crane, or can be proportioned sn' as to reduce the delay of the transient} Ifthe. resistances R5 and'RS, are large, a fairly; small current flowing herein willv The output current willbe fo substantially: a series of relatively square-top create a voltage drop sufliciently large to produce the desired extinguishment of the tubes.

In all such arrangements a battery source 3' of ample capacity is desirable. In fact, in order a '5 to secure the overshooting and wave shaping effect mentioned above, it is preferable that the current supplying capacity of the source B be at leasttwice that required to supply the normal current fioyv through onetubel 1 10 In accordance with Fig? 4", the networks NI or N2 may include rectifiers "I, 8 'of the copper-oxide type either in the primary circuit, in the sec-' ondary circuit, or in both. The effect of these is to make networks NI or N2 substantially unidirectional and, by poling the rectifiers properly, 1 impulses of snfiicientpower to extinguish the gas-filled tube which. is to be extinguished will be avai lable without wasting so much of the available power in the other network which has its input circuit associated with the tube which is not. tobe extinguished. Eurtherrnore, the recifier e a a r du e t el rans'ie m ulse fle 'inginan undesired direction.

The condensers C2, 'C3"'and C4. 25 e s, op on l ow er hey preven he pasa of; con inuousl sew n d rect c rrent filt r ma jb fl siens t eiveith n a ver-all. I V

sfer admitta ce for telegraph signals' and ieqessar ore. u e ne dfio'i, Si nalman that aryv rief, m ulse d s urb n villi not be ubmi ted, nmc en lvo, as to. us esireq reve s l nglar tvgibe mash d tov the t, and Z,v llfQr'mati n With c rcu ts crim ubes; Tespect to the e' menisci.- such lter may a tanhi rans a ns f, the-Amer can nst tut -L ls t i alEneiaeers v9.1. L e se Girl-164 Ap .31% may, beywnpl vedr e i iinlem nt hi n rm ti n t nece sarr.

5,5 il. j ii ar, at, pn oij ma den e o nputIc'incults of tubes. Land/'21s considerable, itfwill be ndes able ansii he es staec s Rm email will be, m l re a These may. e; i h, es s ance- Thus the impedance of the repeater as viewed so from e in ls J andi' i willfb ub a ia x elwthe m isi iance nLanna,

n e i us v discusse he ne works NJ, and N2 have their input circuits'connected tnterini pals L and. Quinn imi itsl nne t d eini lal fii i we i; 131. hev circu t e me s sweetl nrqcqrtiqned; mess networks ma hav g e n ut c rcuits, connec ed t ithe termi-i nelsfi, term als I a 5 ,q n e iedi are-.rnore or through he W ndin sand hey hav a eficial nown. n crmationon f t esi n eirQuiputc rp itsico necteatq ,v v In 'sqi ar aa tn s a i a i o ive. he. essences, a4, Rs, shimi ab value t eenra ef .cts h QQ fied er ra m will be the ame. sq ni h i cinalthe potential drops across R3 and R5 in the case of NI or across R4 and R6 in the case of N2, respectively. Their outputs might be arranged so that NI applies voltage across R4 and R6 while N2 applies voltage across R3 and R5.

What is claimed is:

1. A repeater consisting of a plurality of gaseous discharge tubes each having an anode, a cathode and a control element connected in push-pull relation, and incoming line connected oppositely to the cathode-control element paths of said tubes, connections whereby a discharge through one of said tubes impresses a potential upon the output circuit of the other thereof to interrupt any existing discharge therethrough, said connections including impedance means in the output circuits'of one of said tubes whereby the beginning of current discharge in one of said tubes produces a sudden changeof voltage across said impedance means, an amplifier having its input circuit connected to have said change of voltage applied thereto, and a coupling between the output circuit of said amplifier and the output path of the other tube to impress a large negative voltage upon the anode thereof as an incident to said sudden change.

2. A repeater for voltage or current waves of the direct current impulse type, comprising a pair of gaseous breakdown discharge tubes arranged in push-pull relation, amplifiers each.

v upon the output-anode circuit of the other to having its input circuit connected to impedance means in the output path of one tube to supply amplified reversed voltages to the output path of the other tube in a direction to quench or suppress any existing current flow therein.

3. A repeater consisting of a pair of gaseous discharge tubes each having an anode, a cathode, and a control element connected in push-pull relation, an incoming line connected oppositely to the cathode-control element paths of said tubes and connections wherebya discharge a CD through one of said tubes impresses a potential interrupt any existing discharge therethrough,

said connections comprising an essentially pure resistive impedance for deriving the potential from one tube and an essentially pure resistance impedance for impressing the potential upon the other tube.

4. A repeater for voltage or current waves of age to the anode-cathode circuit of one tube upon the initiation of a discharge in the other.

5. A repeater for voltage or current wavesof the direct current impulse type, comprising a pair of gaseous breakdown discharge tubes arranged in push-pull relation, and a circuit including reverse transformer couplings from a resistance in the output path of each tube to the output circuit of the other, with a rectifier included in the coupling circuit poled in a direction whereby the initiation of a discharge in one tube applies a pulse flowing in the conductive direction of the rectifier tending to extinguish the other.

6. A system in accordance with claim-5 in which the rectifier is in the primary circuit.

7. A system in accordance with claim 5 in which the rectifier is in the secondary circuit.

8. A system in accordance with claim 5 in which rectifiers are included in both the primary and secondary circuits.

KENNETH W. PFLEGER, 

